Fuel Pressure Regulator Valve(FPRV) is integrated with high pressure pump and controls common rail pressure as regulating the quantity of fuel which is delivered to common rail. In order to control rail pressure to be optimum to current driving condition, ECM controls fuel pressure regulator valve operating current(with the method of duty-control) using RPCV signal, RPM and APS signal.
The lower Fuel pressure regulator valve current is, the more fuel is supplied to common rail. Thus it leads rail pressure to be high.
On the contrary, the higher Fuel pressure regulator valve current is, the less fuel is supplied to common rail. Thus it leads rail pressure to be low. Therefore, when Fuel metering unit current becomes "0", as if there is open spot in Fuel metering unit circuit or connector is disconnected, maximum fuel quantity is supplied to common rail, so the pressure of common rail rise to maximum value.
P0253 is set when "0"A in control circuit of Fuel metering unit(integrated with high pressure pump) is detected for more than specified duration. This code is due to open or short to ground in control circuit or Fuel metering unit internal open.
Item | Detecting Condition | Possible Cause | |
DTC Strategy | ● Voltage monitoring | ● FPRV circuit ● FPRV component | |
Enable Conditions | ● IG KEY "ON" | ||
Threshold Value | ● Short to GND - 0.28 sec. ● Wiring open - 0.22 sec. | ||
Diagnostic Time | ● Refer to threshold value | ||
Fail Safe | Fuel Cut | NO | |
EGR Off | NO | ||
Fuel Limit | YES | ||
Check Lamp | YES |
Fuel pressure regulator valve resistance | Operating frequancy |
2.9 ~ 3.15Ω (20℃) | 185 Hz |
